This invention relates to signal processors for radar, sonar and like signal reception systems, and more particularly to sidelobe cancellation circuits for control of jamming, interference and other noise in such systems.
Still more particularly, the present invention constitutes a refinement of the basic intermediate frequency sidelobe canceller circuit disclosed and claimed in U.S. Pat. No. 3,202,990, which issued 24 Aug. 1965 to Paul W. Howells and is assigned to the assignee of the present application. The basic canceller loop of this Howells patent has proven to be effective against a variety of jamming and other interference sources, and it has been sucessfully and extensively used in many signal processor applications in both single loop and multiple loop versions as described in the patent. A modification of the basic multiple loop canceller is disclosed and claimed in the copending application of Kovarik, Howells and Applebaum, Ser. No. 165,259, filed Jan. 9, 1962, also of common assignment, now U.S. Pat. No. 4,044,359.
Cancellation loop saturation control in accordance with the present invention affords significant enhancement of capabilities of sidelobe cancellers of the kind described in these earlier filed cases. Controllability of loop saturation level affords also greater adaptability and thus potentially greater applicability of such cancellers particularly under operation conditions in which difficulties might otherwise be anticipated and, in accordance with the invention, these improvements are accomplished by addition of only relatively very simple and low cost circuit elements to otherwise conventional sidelobe cancellers.